But, I can understand and relate exactly to what you're going through. The only difference (imo) is that my over-active mind has actually led to some pretty bad anxiety that I'm just recently being able to cope with and manage. I was at a point about a year ago where there was so much stuff happening around me and so many things I was constantly trying to process (work, school, private projects, potential startup ideas, relationships, family, etc.) that I would end up in the hospital from panic attacks, seemingly from information overload.
What i did to cope was seek therapy - and I actually only did that for about five sessions until something clicked. I've since been able to simply prioritize things in my mind and ignore things I deemed irrelevant. This has helped immensely. Also, I've taken up meditation to really train my brain into not getting so distracted so I can focus on only one thing at a time when I need to.
You're definitely not alone here. We've spent our entire lives consuming information at a level that we're not actually designed for, it'll take some time to train yourself to slow down and focus on one thing at a time.